Apparatus for the production of artificial filaments



Jan. 1, 1946. s HUNTER 2,391,973

APPARATUS FOR THE PRODUCTION OF ARTIFICIAL FILAMENTS Filed March 30,1942 Archibald 5.Hun"[e1" IIIIIIIIEHHEHIIIWlillllll Patented Jan. 1,1946 APPARATUS FOR THE PRODUCTION OF ARTIFICIAL FILAMENTS ArchibaldStuart Hunter,

Kenmore, N. Y., assignor to E. I. du Pont de Nemours & Company.Wilmington, Dei., a. corporation of Delaware Application March 30, 1942,Serial No. 436,894

4 Claims.

This invention relates to the production of artificial filaments, andmore particularly it relates to the production of artificial filamentshaving an uneven or irregular denier.

The most convenient and generally satisfactory method for producingcontinuous artificial filaments having varying deniers is to give to thestream of filament-forming solution passing through the spinneret, apulsating motion. A number of processes and apparatus have beensuggested for initiating this pulsating motion. In some cases, deviceshave been mounted between the metering pump and the spinneret whichregularly and momentarily interrupt the flow oi filament-formingsolution. It is also known to introduce a pulsating flow offilamentforming solution into the line leading from the metering pump tothe spinneret.

However, where it is desired to produce artificial filaments withfrequent and sharp variations in the denier so as to provide aparticular effect in fabrics composed of the variable denier filaments,the methods and apparatus proposed heretofore are not in generalsatisfactory, principally because the variation in denier obtained wasso slight and gradual that fabrics produced therefrom do not have thedesired appearance. It is further noted that in most cases the thickportion of the filaments. while being of sufficient thickness, are quitelong and not short and sharp as is desired in many cases.

It is, therefore. an object of my invention to provide means for theproduction of artificial filaments having an uneven denier in which theunevenness or irregularity of denier varies frequently and sharply.

It is a further object of my invention to provide means for theproduction of uneven denier yarn, which can be attached to conventionalartificial yarn production mechanisms without extensive change ormodification of such mechanism.

It is another object of the invention to provide a means for changingthe fiow of filament-forming solution passing to a spinning nozzle froman even fiow to a pulsating fiow.

Other objects of the invention will appear hereinafter.

These objects are accomplished by my invention which comprises a gearpump mechanism the rate of delivery of which varies at least 400 timesper minute, said mechanism consisting of a viscose metering pump of thegear type in which a portion of some or the gear teeth has been removed.

My invention will now be described with particular reference to theproduction of artificial filaments produced from viscose. The invention,however, is not restricted to the spinning of viscose but is applicableto the production of artificial filaments from cellulose derivativecompositions in an organic solvent, which will be coagulable in thepresence of heated gases, or it may be applicable to the production ofregenerated cellulose or cellulose derivative filaments from solutionscoagulable in a liquid coagulating bath. It is further applicable to theproduction of filaments from synthetic linear polyamides, polyvinylalcohol, poiyvinyl acetal, polyvinyl acetate, vinyl chloride-vinylacetate interpolymer, polyvinyl chloride. casein, and otherfilament-forming materials.

The invention will be more clearly apparent by reference to thefollowing detailed descriptions taken in connection with theaccompanying drawing, in which Fig. 1 is a diagrammatic elevational viewof a typical fiow system showing flow pulsating device interposedbetween the candle filter and the spinneret.

Fig. la. is an elevation of a typical viscose metering pump with one ofthe side components of its casing removed to show the disposition of thegears therein and the position of the inlet and outlet ports relative tothe gears.

Fig. 2 is a side view of the meshing gears used in the standard viscosemetering pump of Fig. in. modified in accordance with my invention.

Fig. 3 is a top view or the gears of Fig. 2.

Fig. 4 is a side view partly in section and shows a differentmodification of the gears of Fig. 2.

Fig. 5 is a top view of the modification of Fig. 4.

Fig. 6 shows still another modification of the gears of Fig. 2.

Fig. '7 is a top view of the modification of Fig. 6.

Referring to Fig. l of the drawing, reference numeral l designates thepipe line for passing the viscose through pipe 2 to metering pump 5. Theconventional viscose gear type pump 5 is driven through gears and driveshaft (not shown). The viscose is pumped from the metering or spinningpump 5 through pipe I to a candle filter Ill and then through pipe 9 toa modified metering pump 8 which, like pump 5, is driven by conventionalmeans not shown. Pipe 9 should not have an inside diamete greater than/21,", and preferably it should be it". The modified pump 8 breaks upthe regular flow of the viscose and transmits said viscose in apulsating flow through gooseneck 3 to the spinneret l2. The modifiedpump 8, for the best results, should be as close as possible to thesplnneret to prevent dampening out or the pressure surge. The modifiedpump should be placed between the candle filter and the splnneret forthe best results. In addition, the candle filter ill and the gooseneckshould be made of nonstretchable material to prevent a diminishing ofthe pressure surge effect.

For optimum results, the pressure on the viscose spinning solution atthe inlet port of pump 8 should be greater than the pumping pressure ofsaid pump. This will prevent pipe 8 from being sucked dry. Metering pumpi supplies viscose to pump 8 at a pressure which should be sufllcient tokeep the inlet ports of pump 8 filled at all times. If the pumpingaction 01' pump I exceeds that of pump 5, a bypass 29 around pump 8 maybe installed to allow viscose to pass from pipe 3 to pipe 9 to preventpipe 9 from being Sucked dry of viscose. Pipe 29 should be of smalldiameter, for example, 1'; inch.

1 will now describe how the conventional gear ty e spinning pump ismodified to impart a pulsating fiow to the spinning solution carriedtherethrough. Referring to Figs. la, 2 and 3, reference numerals i3 andI3 indicate the meshing gears of the conventional pump, the teeth I4 andII of which normally coact to free a non-pulsating flow of spinningsolution to the spinneret. Gears l3 and I3 are disposed in a casingindicated generally by the reference numeral it, which casing isprovided with the usual fluid inlet and outlet ports I! andrespectively. According to my invention one side of each tooth of a roupof adjacent teeth of gear i3 is removed, and the same side of each toothof a corresponding group of teeth of gear I3 is removed, leaving theremainin teeth of gear I 3 and corresponding remaining teeth of gear l3untouched. As a result there is a pocket or channel l5 formed betweenthe gears to the sides of the teeth which have been partly cut away.Therefore, in place of an even fiow of spinning solution through thepump, gears I3 and ill by reason of pocket I! coact to deliver apulsating flow, the pulsations of which vary in frequency and amplitudein accordance with the speed of the pump and the number, size and shapeof the pockets formed between the gears.

Figs. 4 and 5 show an inner pocket II in the gears l3 and i3, whichpocket has a tapered shape. When these gears revolve, the tapered rearportion 01' the pocket aids in forming the thin connecting section ofthe filament between the thickened portions, and therefore aids inpreventing broken filaments.

Figs. 6 and 7 illustrate another modification of the gears shown in Fig.2. Gear is is shown with some of the teeth I unmodified, while parts ofother teeth have been removed to provide an inner pocket I1 in theteeth. The coacting gear i3 is modified in the same way as gear it.

In the practice of the invention, a metered quantity of viscose ispassed continuously from the spinning pump 5 through candle filter illto the modified gear pump mechanism 8, which pulsates at least 400 timesper minute. The viscose, after it has passed through the special gearedvalve mechanism, moves along to the spinneret in very short rapidsurges. The variable delivery of viscose to the spinneret, asrepresented by the short rapid pulsations, in combination with aconstant drawofl produces a yarn which has thickened portions atintervals along the length of individual filaments.

The following specific examples will more clearly illustrate theoperation of the present invention under actual operating conditions.Percentage parts are by weight unless otherwise indicated.

Example I A 7% cellulose, 6% caustic bright viscose is metered at therate of 24 grams per minute through a metering pump (No. 1 Zenith pump)passed through a candle filter, and fed through a M; inch line to amodified pump (No. Zenith pump). In this modified pump, each gear hastwo 9-tooth side pockets. The pockets are made by cutting away inch ofthe sides of 9 adjacent teeth. The two pockets on a given gear areopposite each other and have four unaltered adjacent teeth intervening.The gears are so positioned in the pump that the pockets of the driveand the driven gear come together and thus form an open valve directlythrough the pump twice each time the gear is rotated. This pum isrotated at 1140 R. P. M. On leaving this new pump, the viscose passesthrough a 10 inch gooseneck and through a 40 hole spinneret into acoagulating regenerating bath containing 9% sulfuric acid, 19% sodiumsulfate, 4% glucose, and 0.7% zinc sulfate. The bath temperature is 45'C. and the bath travel 54 inches. The yarn is collected on a bobbin at2520 inches per minute. After normal processing, the yarn is thrown to 3turns per inch, at which time it has a denier of 260. The filaments ofthe yarn produced by the above procedure have thick portions along thelength thereof. The thick portions are approximately inch in length withan intervening space between them of approximately 2 inches.

Example 11 A 7% cellulose, 4% caustic dull viscose is metered at therate of 16 grams per. minute through a metering pump (No. l Zenith pump)and passed through a inch line to a modified pump (No. l Zenith pump).Each gear in this modified pump has a one tooth center tooth pocket withtwo teeth tapered on each side (diamond shaped). These pockets are madeby cutting a 0.032 inch wide channel to the depth of one tooth on a inchradius with a Woodruif cutter. The gears are so positioned in the pumpthat the pockets of the drive and the driven gear come together and thusform an open valve directly through the pump, once for each revolution.This pump is rotated at 850 R. P. M. On leaving thi modified pump, theviscose passes through a 10 inch gooseneck and through a hole spinneretinto a 6% sulfuric acid, 24% sodium sulfate, 0.7% zinc sulfatecoagulating regenerating bath. The bath temperature is 45 C. and thebath travel 54 inches. The yarn is collected on a bobbin at 2520 inchesper minute. .After normal processing, the yarn is thrown to 3 turns perinch, at which time it has a denier of 170. The filaments of the yarn soproduced have thick portiors about if; inch in length at a frequency ofabout one every 3 inches along the length of said filaments.

Example III The pulsating flow of viscose from the modified pump ofExample 11 is combined with a stream of viscose from an adjacentnormally spinning position. The junction of the two streams of viscose,one a uniform flow and the other a pulsating fiow is made at thegooseneck just in front of the spinneret. An uneven denier yarn similarto that described in Exampl 11 is obtained.

It is to be understood, of course, that my invention is not limited tothe exact details of construction, arrangement and operation describedabove for purposes of illustration, but is susceptible rather to manychanges and modifications.

Thus, in the flow disrupting device, the pocket length may vary from oneto all but a few of the teeth. The shape of the pocket ma also vary. Itmay be along one side of the gear or it may be through the centerportion of the gear teeth. When the pocket is in the center of the gearteeth, it may be rectangular in shape, diamond shaped, triangular, orany other desired form. While various pocket sizes and designs aresuitable, a preierred design consists of a center pocket in which partsof 4 teeth have been removed, said pocket being triangular as shown inFig. 4. It is to be noted that in the preparation of all of these gears,a portion of each tooth is to be left intact so that there can becontinuous meshing of the teeth during their revolutions. This allows anoperation of continuous motion in contrast to an eccentric motion, whichis more diflicult to handle mechanically.

In normal operation, metering pumps of this type do not run over 100 R.P. M. However, in order for the modified pump to give the short rapidpulsations of the spinning solution, it must be run at such a speed thatthe rate of delivery of the spinning solution therefrom varies at least400 times per minute. Preferably, the rate of delivery should be variedas often as 1,000 or 1,500 times a minute and in some cases even morefor the best results.

The apparatus of the present invention, which makes it possible to veryrapidly vary the fiow of viscose to the spinneret, is unique and makesit possible for the first time to spin continuously yarns of unevendenier characterized by the fact that the thickened portions are sharpand abrupt rather than long and tapering. For the most part, thethickened portions are not more than 1% inches in length and are spacedfrom 1 to inches apart. The uneven denier yarn containin; these shortthick portions gives novel effects when used in knitting and weavingoperations. They may be used alone or combined with other yarns. It isfurther possible to regularly vary the shape and spacing of thethickened portions along the length 01' the filaments by using differentsize pockets on the same gear and by irregularly spacing the pockets onthe gears.

I claim:

1. A gear pump comprising a. casing having fluid inlet and outlet portsand two intermeshing liquid-conveying gears disposed in said casing andpositively driven to deliver a continuous stream of liquid, each of saidgears having registering complete teeth and registering teeth partly cutaway to form one or more pockets all of the complete teeth of one gearbeing in register with all of the complete teeth of the other gearwhereby the gears operate to impart a pulsating flow to the stream ofliquid.

2. In an apparatus for the production of artificial filaments comprisinga spinneret, a filter, and a liquid pump for transferring artificialfilamentforming material in a non-pulsating iiow through said filter andto said spinneret, the improvement which comprises a second liquid pumplocated between the filter and the spinneret, said pump comprising twointermeshing, liquid-conveying gears disposed in a casing provided withfluid inlet and outlet ports, said gears being positively driven todeliver a continuous stream of artificial filament-forming materialdirectly to the spinneret, each of said gears having registeringcomplete teeth and teeth partly cut away to form one or more pocketswhereby the gears operate to pass a pulsating flow of the artificialfilament-forming material to the spinneret.

3. In an apparatus for the production of artificial filaments comprisinga spinneret, a filter, and a liquid pump for transferring artificialfilamentforming materials in a non-pulsating fiow through said filterand to said spinneret, the improvement which comprises a second liquidpump located between the filter and the spinneret, said pump comprisingtwo intermeshing, liquid-conveying gears disposed in a casing providedwith fluid inlet and outlet ports, said gears being positively driven todeliver a continuous stream oi artificial filament-forming materialdirectly to the spinneret, each of said gears having registeringcomplete teeth and teeth having a side por tion cut away to form one ormore side pockets, whereby the gears operate to pass a pulsating flow oithe artificial filament-forming material to the spinneret.

4. In an apparatus for the production of variable denier artificialfilaments comprising a spinneret, a filter, and a liquid pump fortransferring artificial filament-forming materials in a nonpulsatingflow through said filter and to said spinneret, the improvement whichcomprises a second liquid pump located between the filter and thespinneret, said pump comprising two intermeshing, liquid-conveying gearsdisposed in a casing provided with fluid inlet and outlet ports, saidgears being positively driven to deliver a continuous stream ofartificial filament-forming material directly to the spinneret, each ofsaid gears having registering complete teeth and teeth having thecentral portion cut away to form one or more central pockets, wherebythe gears operate to pass a pulsating iiow of the artificialfilamenttorming material to the spinneret.

ARCHIBAID STUART HUNTER.

CERTIFICATE OF CORRECTION.

Patent No. 2,59 ,973-

January 1, 19l 6.

ARCHIBALD STUART HUNTER It is hereby certified that error of the abovenumbered patent requiri.

0nd column, line 55, for "3/ inch" Letters Patent should be read withthis correction therein that the same may conform to the record of thecase 1 Signed and sealed this 9th day of April,

appears in the printed specification ng correction as follows:

read "5/14 inch-- Page 2, secand that the said n the Patent Office.

Leslie Frazer hind. r-mininner of Patents- It is to be understood, ofcourse, that my invention is not limited to the exact details ofconstruction, arrangement and operation described above for purposes ofillustration, but is susceptible rather to many changes andmodifications.

Thus, in the flow disrupting device, the pocket length may vary from oneto all but a few of the teeth. The shape of the pocket ma also vary. Itmay be along one side of the gear or it may be through the centerportion of the gear teeth. When the pocket is in the center of the gearteeth, it may be rectangular in shape, diamond shaped, triangular, orany other desired form. While various pocket sizes and designs aresuitable, a preierred design consists of a center pocket in which partsof 4 teeth have been removed, said pocket being triangular as shown inFig. 4. It is to be noted that in the preparation of all of these gears,a portion of each tooth is to be left intact so that there can becontinuous meshing of the teeth during their revolutions. This allows anoperation of continuous motion in contrast to an eccentric motion, whichis more diflicult to handle mechanically.

In normal operation, metering pumps of this type do not run over 100 R.P. M. However, in order for the modified pump to give the short rapidpulsations of the spinning solution, it must be run at such a speed thatthe rate of delivery of the spinning solution therefrom varies at least400 times per minute. Preferably, the rate of delivery should be variedas often as 1,000 or 1,500 times a minute and in some cases even morefor the best results.

The apparatus of the present invention, which makes it possible to veryrapidly vary the fiow of viscose to the spinneret, is unique and makesit possible for the first time to spin continuously yarns of unevendenier characterized by the fact that the thickened portions are sharpand abrupt rather than long and tapering. For the most part, thethickened portions are not more than 1% inches in length and are spacedfrom 1 to inches apart. The uneven denier yarn containin; these shortthick portions gives novel effects when used in knitting and weavingoperations. They may be used alone or combined with other yarns. It isfurther possible to regularly vary the shape and spacing of thethickened portions along the length 01' the filaments by using differentsize pockets on the same gear and by irregularly spacing the pockets onthe gears.

I claim:

1. A gear pump comprising a. casing having fluid inlet and outlet portsand two intermeshing liquid-conveying gears disposed in said casing andpositively driven to deliver a continuous stream of liquid, each of saidgears having registering complete teeth and registering teeth partly cutaway to form one or more pockets all of the complete teeth of one gearbeing in register with all of the complete teeth of the other gearwhereby the gears operate to impart a pulsating flow to the stream ofliquid.

2. In an apparatus for the production of artificial filaments comprisinga spinneret, a filter, and a liquid pump for transferring artificialfilamentforming material in a non-pulsating iiow through said filter andto said spinneret, the improvement which comprises a second liquid pumplocated between the filter and the spinneret, said pump comprising twointermeshing, liquid-conveying gears disposed in a casing provided withfluid inlet and outlet ports, said gears being positively driven todeliver a continuous stream of artificial filament-forming materialdirectly to the spinneret, each of said gears having registeringcomplete teeth and teeth partly cut away to form one or more pocketswhereby the gears operate to pass a pulsating flow of the artificialfilament-forming material to the spinneret.

3. In an apparatus for the production of artificial filaments comprisinga spinneret, a filter, and a liquid pump for transferring artificialfilamentforming materials in a non-pulsating fiow through said filterand to said spinneret, the improvement which comprises a second liquidpump located between the filter and the spinneret, said pump comprisingtwo intermeshing, liquid-conveying gears disposed in a casing providedwith fluid inlet and outlet ports, said gears being positively driven todeliver a continuous stream oi artificial filament-forming materialdirectly to the spinneret, each of said gears having registeringcomplete teeth and teeth having a side por tion cut away to form one ormore side pockets, whereby the gears operate to pass a pulsating flow oithe artificial filament-forming material to the spinneret.

4. In an apparatus for the production of variable denier artificialfilaments comprising a spinneret, a filter, and a liquid pump fortransferring artificial filament-forming materials in a nonpulsatingflow through said filter and to said spinneret, the improvement whichcomprises a second liquid pump located between the filter and thespinneret, said pump comprising two intermeshing, liquid-conveying gearsdisposed in a casing provided with fluid inlet and outlet ports, saidgears being positively driven to deliver a continuous stream ofartificial filament-forming material directly to the spinneret, each ofsaid gears having registering complete teeth and teeth having thecentral portion cut away to form one or more central pockets, wherebythe gears operate to pass a pulsating iiow of the artificialfilamenttorming material to the spinneret.

ARCHIBAID STUART HUNTER.

CERTIFICATE OF CORRECTION.

Patent No. 2,59 ,973-

January 1, 19l 6.

ARCHIBALD STUART HUNTER It is hereby certified that error of the abovenumbered patent requiri.

0nd column, line 55, for "3/ inch" Letters Patent should be read withthis correction therein that the same may conform to the record of thecase 1 Signed and sealed this 9th day of April,

appears in the printed specification ng correction as follows:

read "5/14 inch-- Page 2, secand that the said n the Patent Office.

Leslie Frazer hind. r-mininner of Patents-

